Fuel burner

ABSTRACT

A fuel burning apparatus comprising an air register, a liquid fuel burner and a gas fuel burner of unitary construction, the latter including a nozzle portion for conveying the gas fuel, a plenum portion disposed downstream gas flow-wise of the nozzle portion and in fuel receiving relationship therewith, an annular plate member interposed between the nozzle and plenum portions and connected thereto, and a plurality of individual spuds flow communicating with the plenum portion for discharging the gas fuel therefrom.

United States Patent 1 Clark 541 FUEL BURNER [75] Inventor: Merle Myron Clark, Barberton,

Ohio

[73] Assignee: The Babcock & Wilcox Company,

New York, NY.

[22] Filed: July 29, 1971 21 Appl. No.: 167,193

[52] US. Cl. ..431/l88 [51] Int. Cl ..F23m 5/00 [58] Field of Search ..43l/l67,l74,181,187,188, 431/189 [56] References Cited UNITED STATES PATENTS 2,826,249 3/1958 Poole ..43l/l74 51 Jan.16,1973

Reilly et al ..43l/l88 X Ceely ..431/l74 Primary Examiner-Edward G. Favors Att0rneyJ. Maguire [57] ABSTRACT 12 Claims, 5 Drawing Figures PATENTEDJAN 15 1973 SHEET 2 BF 2 FUEL BURNER BACKGROUND OF THE INVENTION The present invention relates to a fuel burning apparatus and more particularly to an improved gas fuel burner to be fired alone or in combination with a liquid fuel burner.

The modern trend has been toward maximization of operating availability of steam generating units by providing dual fuel burners such as the type disclosed in US Pat. No. 3,349,826. These burners are capable of burning either oil or gas, separately or in combination, depending on the amount and availability of the particular fuel. Combination oil and multiple spud gas burners as disclosed in the aforementioned patent, while found to have excellent operating characteristics, proved somewhat difficult to maintain and repair due to inherently crowded constructure resulting from the multiplicity of interrelated and closely spaced components.

SUMMARY OF THE INVENTION The present invention is directed at an improved fuel burning apparatus for burning gas or oil, separately or in combination, and includes a fuel gas burner of unitary construction which is easily removable for maintenance and repair and provides ready access to associated components of the fuel burning apparatus.

In accordance with the invention, there is provided an improved fuel burning apparatus, a portion thereof being disposed within a windbox to which combustion air is supplied and which is formed between adjacently spaced furnace and burner walls of a steam generating unit. The burner wall is formed with an access port for admitting that portion of the fuel burning apparatus which normally resides in the windbox whereas the furnace wall is formed with a burner throat which discharges the products of combustion from the fuel burning apparatus into the furnace chamber. The fuel burning apparatus includes a register assembly having a plurality of individually adjustable arcuate blade members for discharging the combustion air through the burner port in whirling high velocity streams so as to promote the mixing of air and fuel thereby achieving complete combustion of the fuel. The blade members may be positioned to direct the combustion air along either a clockwise or counterclockwise whirling path as viewed from the front of the burner. The fuel burning apparatus also includes a gas burner of unitary construction, at least a portion thereof extending through the access port and into the windbox. The gas burner comprises an open-ended nozzle portion which has a flanged inlet end for connection to the gas fuel supply line, a plenum portion disposed downstream gas flowwise of the nozzle and in fuel receiving relationship therewith, an annular plate member interposed between the nozzle and plenum portions and weldably connected thereto, a plurality of individual spuds flow communicating with the plenum chamber and projecting therefrom to discharge the gas into the combustion air stream and separate first and second guide tubes each capable of accommodating the passage of a liquid fuel burner through the access port and into the windbox. The annular plate member is sized to overlap the burner wall access port and effect a closure thereof by being detachably mounted to the burner wall, e.g., by

bolting the plate to the wall. Thus the simple steps of detaching the fuel supply lines from the gas and liquid fuel burners and unbolting the annular plate from the burner wall provides ready access for maintenance and repair of the gas and liquid fuel burners as well as the igniter, impeller plate, register assembly and other components associated with the fuel burning apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT In the illustrated embodiment disclosed in the drawings, the burner assembly is shown as adapted for a fuel burning apparatus having both a gaseous and liquid fuel burner and applied to a furnace having a refractory wall formed with a burner throat. It should be understood, however, that the invention is equally applicable for burners using gaseous fuel alone.

Referring to FIG. 1, reference numeral 10 is directed I to a refractory lined furnace front wall having a circular opening 12 in which the burner throat 14 is located. A burner wall 16 having an access port 18 is spaced from the front wall 10. The space between the burner and front walls forms a windbox or passageway 20 to which combustion air is delivered from a forced draft fan (not shown). The burner throat I4 is formed of a short cylindrical section 22 connected at its discharge end with a flaring section 24 and at its inlet end with the smaller diameter end of a frusto-conical section 26. The sections of burner throat 14 are formed of suitable refractory material. The fuel burning apparatus 27 includes a cylindrical register assembly 28 which is located within the windbox 20 and is suitably supported therefrom and arranged to receive the combustion air for discharge through the burner throat 14. The register assembly 28 has its longitudinal axis 30 coaxial with the longitudinal axis 32 of the burner throat I4 and includes spaced front and back annular plates 34 and 36, respectively, and a plurality of separate blades or vanes 38 of arcuate cross-section and circumferentially arranged and pivotally mounted between the front and back plates 34 and 36 so as to be rotatable about their axes which are substantially parallel with the projected longitudinal axis 32 of the burner port 14. Each of the blades 38 are individually adjustable by turning the shaft 40 through an adjustment nut 42 located on the front of plate 34. The register assembly 28 is of symmetrical construction so as to permit reversal of the blades 38 thereby changing the direction of rotation of the combustion air being discharged through the burner throat. The front plate 34 includes a cylindrical housing 43 extending into the windbox 20 between the front plate 34 and the vanes 38 thereby forming a shielded air space therebetween and the back plate 36 includes a frusto-conical section 44 which is inserted through a portion of opening 12 and lines the frusto conical section 26 of the burner throat 14. An ignition device 46 is provided for lighting the gas and liquid fuel burners 60 and 61, respectively, and includes the electrical junction box 48, fuel intake chamber 50, fuel conduit 52, electric lead 54, insulators 56 and ignition chamber 58. The gas burner 60 is of unitary construction and has a portion thereof extending through the access port 18 and into the windhox 20 and the burner throat 14. The gas burner 60 is formed with an open ended nozzle portion 62 for conveying the gas fuel, a plenum portion 76 having a longitudinal axis 77 coaxial with the longitudinal axis 32 of the burner throat 14, is disposed downstream gas flowwise of the nozzle 62 and in fuel receiving relationship therewith, an annular plate member 72 is interposed between the nozzle and plenum portions 62 and 76, respectively, and weldably connected thereto. The plate member 72 is detachably mounted to the front face of plate 34 by bolts 74 and has a longitudinal axis 35 coaxial with the longitudinal axis 32 of the burner throat 14, a plurality of individual spuds 88 flow communicate with the interior of the plenum portion 76 and are arranged to discharge the gas fuel into the combustion air stream. Each of the spuds 88 includes an elongated conduit segment 90 and a cap 96 weldably connected thereto, the cap 96 being formed with a perforated tip end 97 for the discharging of gas fuel into the combustion air stream. The longitudinal axis 91 of each of the conduits 90 is inclined with respect to the longitudinal axis 77 of the plenum portion 76 and the longitudinal axis 95 of each of the caps 96 is parallel to the longitudinal axis 32 of the burner throat 14.

In the embodiment shown, a liquid fuel burner 61 is used in combination with the gas burner 60 as part of the fuel burning apparatus 27. The gas burner 60 includes separate first and second guide tubes 81 and 83, respectively, to accommodate the passage therethrough of the liquid fuel burner 61 and its associated distance piece 63. The first guide tube 81 has a longitudinal axis 85 coaxial with the longitudinal axis 32 of the burner throat 14 and the second guide tube 83 has a longitudinal axis 87 inclined with respect to the longitudinal axis 32. The distance piece 63 is axially adjustable along the longitudinal axis 81 of the first guide tube 85 and can be locked in a selected position with the bolt 89. The inlet end 65 of the distance piece 63 is threaded to receive the yoke assembly 49 which is connected to the liquid fuel and atomizing steam lines (not shown). The discharge end 67 of the yoke 49 is connected to the atomizer assembly 69 for the through passage of fuel and atomizing steam. A leak-proof fit between the'yoke 49 and the atomizer 69 is achieved by introducing a gasket (not shown) between the mating surfaces and applying pressure with locking device 59. Barrel tube 57 is connected at its inlet end to the atomizer assembly 69 and at its outlet end to a sprayer plate (not shown). Attached to a support ring 55 at the distal end of distance piece 63 is an impeller deflector 53 in the shape of a truncated cone, concentrically disposed about the longitudinal axis 32 of the burner throat 14. The second guide tube 83 is equipped with components substantially identical to the aforementioned components associated with the liquid fuel burner 61 with the exception that the same impeller 53 is used in both instances. For the sake of clarity the like components, used on the second guide tube 63 and associated with a like liquid fuel burner, are not shown. During the normal operation of the fuel burning apparatus 27, the liquid fuel burner 61 extends through the first guide tube 81. At a frequency of about once every 8 hours for a duration of about 10 minutes, a like liquid fuel burner (not shown) will be inserted through the second guide tube 83 and will sustain combustion while the liquid fuel burner 61 extending through the first guide tube 81 is removed for cleaning. The use of an auxiliary liquid fuel burner through the guide tube 83 affords uninterrupted operation of the steam generating unit while permitting the required periodic cleaning and inspection of the main liquid fuel burner 61.

Referring to FIG. 2, there is illustrated the rear end view of the fuel burning apparatus 27 showing the refractory lined furnace front wall 10 formed with the circular opening 12 and including the burner throat 14 and the flared section 24 thereof. There is also shown the perforated tip end 97 of each of four spuds 88 circumferentially equispaced about the impeller 53, the latter being notched at 39 to accommodate the auxiliary liquid fuel burner (not shown) which extends through the second guide tube 83. While the present embodiment is shown with four spuds, it is to be appreciated that the invention may have a greater or lesser number of spuds depending on the capacity of the fuel burning apparatus 27.

Referring to FIG. 3, there is illustrated the front end view of the fuel burning apparatus 27 showing the annular plate member 72 detachably mounted through bolts 74 onto the front plate 34 of the register assembly 28. The nozzle portion 62 is shown with its outlet end concentric with the plate member 72 and the first guide tube 81 extending therethrough. The second guide tube 83 is shown extending through the plate member 72 and having its front end closed-off by a seal plug 33 which is inserted therein to prevent leakage of combustion air from the windbox when the auxiliary burner (not shown) is not in use. There is also shown the front end of the ignition device 46 and an observation window 31. The adjusting nuts 42 are accessible from the front face of plate 34 and are shown as associated with one of each of four register blades. While the present embodiment is shown with four register blades, it is to be appreciated that the invention may have a greater or lesser number of register blades depending on the capacity of the fuel burning apparatus 27 Referring to FlG. 4, there is illustrated the gas burner in its unitary construction including the open-ended nozzle portion 62 having an inlet end 64 fitted with a flange section 66 formed with bolt holes 68 for enabling the nozzle inlet end 64 to be detachably connected to a gas fuel supply line (not shown). The outlet end 70 of the nozzle portion 62 is weldably connected to the front face of the annular plate member 72 and is concentric therewith. The plate member 72 is formed with holes 75 for enabling the gas burner 60 to be detachably mounted to the fuel burning apparatus. The plenum portion 76 includes a cylindrical-shaped seg ment 78 having its inlet end 80 weldably connected to the back side of the annular plate member 72 and its outlet end 82 capped by a dish-shaped closure segment 84. The gas burner 60 is provided with a plurality of spuds 88 for discharging the gas fuel into the combustion air stream. Each of the spuds 88 is formed of a conduit segment 90 having an inlet end 92 weldably connected to the closure segment 84 of the plenum portion 76 and flow communicating with the interior thereof through the openings 85 formed in the closure segment 84. The inlet ends 92 of the conduits 90 are disposed in a circular pattern radially spaced from and equiangularly displaced about the longitudinal axis 77 of the plenum portion 76. The outlet end 94 of each conduit 90 is weldably connected to a cap 96 formed with a perforated tip end 97 having a plurality of discharge orifices 99. A collar plate 95, acting as a flame shield, encircles the interconnected ends of the conduit 90 and associated cap 96. The longitudinal axis 91 of each of the conduits 90 is inclined with respect to the longitudinal axis 77 of the plenum portion 76 and the longitudinal axis 95 of each of the caps 96 is parallel to the longitudinal axis 32 of the burner throat 14 as shown in FIG. 1 ofthe drawings.

The gas burner 60 shown in FIG. 4 is capable of being used in combination with a liquid fuel burner and includes a first guide tube 81 and a second guide tube 83. The first guide tube extends through a section of nozzle portion 62 including the outlet end 70 thereof and through the central opening in annular plate 72 and through the plenum portion 76 and its closure segment 84. The first guide tube 81 is weldably connected to the wall of the nozzle portion 62 and the closure segment 84 at the respective points of penetration. The second guide tube 83 extends through the annular section of the plate member 72 and is weldably connected to the plate member 72 at the point of penetration. The first guide tube 81 includes the bolt 89 and the second guide tube 83 includes the bolt 73, each of the bolts extending through the walls of respective guide tubes and adjustable to lock the liquid fuel burner in a selected position.

It is to be understood that the expression weldably connected as used throughout the disclosure is intended to mean seal-welding, i.e. the welding together of abutting surfaces which renders the joint between the welded surfaces absolutely leakproof and in the present case meets the requirement of the gas burner structure which is fabricated to withstand at least p.s.i. gas fuel pressure.

Referring to FIG. 5, there is illustrated the front end view of the gas burner 60 showing the annular plate member 72 formed with circumferentially distributed bolt holes 75 and including a circular opening 41 for allowing the passage therethrough of the ignition device 46 and a circular opening 45 for providing visual access in conjunction with the observation window 31. The nozzle portion 62 is L-shaped and has its outlet end concentric with the plate member 72 and its inlet end fitted with a flange section 66. The first guide tube 81 extends through the outlet end of nozzle portion 62 and is concentric therewith. The second guide tube 83 extends through the plate member 72. Also shown are the locking bolts 89 and 73 associated with the first and second guide tubes, respectively.

The present invention is particularly adaptable to the repair and/or replacement of components associated with the fuel burning apparatus 27 and located within the windbox 20 and/or burner throat 14. Ready access to these components is achieved by detaching the atomizing steam and liquid fuel supply lines (not shown) from the yoke 49 and unbolting the flange 66 from the gas fuel supply line (not shown), thereafter unbolting the annular plate member 72 from the front plate 34 and removing the plate member 72, and the components supported thereby, out of the windbox 20. Moreover, access to components remaining in the windbox, e.g. the register assembly 28, may be had through the access port 18 formed in the burner wall 16.

The present invention is also particularly well suited for use with low pressure gas fuel as a result of the unique arrangement of components which make-up the gas burner 60. In the operation of gas burners, it is essential that the gas fuel discharge pressure be adequate to maintain stable flame ignition throughout the burner operating range, thus the gas fuel must be equally distributed to all of the spuds 88, particularly at minimum operating capacity where uneven distribution of fuel might result in an unsafe operating condition if loss of flame ignition should occur at any of the spuds 88 due to insufficient gas fuel discharge pressure. Accordingly, the present invention has a gas burner 60 which achieves equidistribution of gas fuel to all of the spuds 88 by having the outlet end of the nozzle portion 62 coaxial with the longitudinal axis 77 of the plenum portion 76 and having the inlet ends 92 of spuds 88 disposed in a circular pattern radially spaced from and equiangularly displaced about the longitudinal axis 77 of plenum portion 76.

While in accordance with the provisions of the statutes there is illustrated and described herein a specific embodiment of the invention, those skilled in the art will understand that changes may be made in the form of the invention covered by the claims, and that certain features of the invention may sometimes be used to advantage without a corresponding use of the features.

What is claimed is:

1. In combination with a furnace wall having a burner throat, a burner wall having a burner access port, said furnace and burner walls being spaced from one another to form a windbox therebetween to which combustion air is supplied, an improved fuel burning apparatus including a register assembly disposed within the windbox for discharging the combustion air through the burner port, a gas burner of unitary construction, at least a portion thereof extending through the access port and into the windbox, said gas burner comprising an open-ended nozzle portion for conveying the gas, a plenum'portion disposed downstream gas flow-wise of said nozzle and in fuel receiving relationship therewith, an annular plate member interposed between the nozzle and plenum portions and connected thereto, said plate member being detachably mounted to the burner wall, the plate member having a longitudinal axis coaxial with the longitudinal axis of the burner throat, a plurality of individual spuds flow communicating with the plenum portion, said spuds being disposed for discharging the gas into the combustion air stream.

2. The combination according to claim 1 wherein the nozzle portion has an outlet end weldably connected to said plate member and concentric therewith.

3. The combination according to claim 1 wherein the plenum portion has an inlet end weldably connected to the plate member, said plenum portion having a longitudinal axis coaxial with the longitudinal axis of the burner throat.

4. The combination according to claim 3 wherein the plenum portion is formed of a cylindrical segment including the end weldably connected to said plate member and an outlet end capped by a dish-shaped closure member.

5. The combination according to claim 4 wherein each of the spuds is formed of an elongated conduit having an inlet end weldably connected to said closure segment and an outlet end weldably connected to a cap, said cap including a perforated tip end.

6. The combination according to claim 5 wherein the conduit inlet ends are disposed in a circular pattern radially spaced from and equiangularly displaced about the longitudinal axis of said plenum portion.

7. The combination according to claim 5 wherein the longitudinal axis of each of said conduits is inclined with respect to the longitudinal axis of said plenum por- .tion.

8. The combination according to claim 5 wherein the longitudinal axis of each of the caps is parallel to the longitudinal axis of said burner throat.

9. The combination according to claim 5 wherein a collar plate encircles the interconnected ends of the conduit and cap associated with each of said spuds.

10. The combination according to claim 1 including a liquid fuel burner, a separate first and second guide tube associated with the gas burner, each of said guide tubes being capable of accommodating the passage of said liquid fuel burner through the access port and into the windbox.

11. The combination according to claim 10 wherein the first guide tube has a longitudinal axis coaxial with the longitudinal axis of the burner throat, said first guide tube extending through the nozzle and plenum portions and being weldably connected thereto.

12. The combination according to claim 10 wherein the second guide tube has a longitudinal axis inclined with respect to the longitudinal axis of the burner throat, said second guide tube extending through the plate member and being weldably connected thereto. 

1. In combination with a furnace wall having a burner throat, a burner wall having a burner access port, said furnace and burner walls being spaced from one another to form a windbox therebetween to which combustion air is suppLied, an improved fuel burning apparatus including a register assembly disposed within the windbox for discharging the combustion air through the burner port, a gas burner of unitary construction, at least a portion thereof extending through the access port and into the windbox, said gas burner comprising an open-ended nozzle portion for conveying the gas, a plenum portion disposed downstream gas flow-wise of said nozzle and in fuel receiving relationship therewith, an annular plate member interposed between the nozzle and plenum portions and connected thereto, said plate member being detachably mounted to the burner wall, the plate member having a longitudinal axis coaxial with the longitudinal axis of the burner throat, a plurality of individual spuds flow communicating with the plenum portion, said spuds being disposed for discharging the gas into the combustion air stream.
 2. The combination according to claim 1 wherein the nozzle portion has an outlet end weldably connected to said plate member and concentric therewith.
 3. The combination according to claim 1 wherein the plenum portion has an inlet end weldably connected to the plate member, said plenum portion having a longitudinal axis coaxial with the longitudinal axis of the burner throat.
 4. The combination according to claim 3 wherein the plenum portion is formed of a cylindrical segment including the end weldably connected to said plate member and an outlet end capped by a dish-shaped closure member.
 5. The combination according to claim 4 wherein each of the spuds is formed of an elongated conduit having an inlet end weldably connected to said closure segment and an outlet end weldably connected to a cap, said cap including a perforated tip end.
 6. The combination according to claim 5 wherein the conduit inlet ends are disposed in a circular pattern radially spaced from and equiangularly displaced about the longitudinal axis of said plenum portion.
 7. The combination according to claim 5 wherein the longitudinal axis of each of said conduits is inclined with respect to the longitudinal axis of said plenum portion.
 8. The combination according to claim 5 wherein the longitudinal axis of each of the caps is parallel to the longitudinal axis of said burner throat.
 9. The combination according to claim 5 wherein a collar plate encircles the interconnected ends of the conduit and cap associated with each of said spuds.
 10. The combination according to claim 1 including a liquid fuel burner, a separate first and second guide tube associated with the gas burner, each of said guide tubes being capable of accommodating the passage of said liquid fuel burner through the access port and into the windbox.
 11. The combination according to claim 10 wherein the first guide tube has a longitudinal axis coaxial with the longitudinal axis of the burner throat, said first guide tube extending through the nozzle and plenum portions and being weldably connected thereto.
 12. The combination according to claim 10 wherein the second guide tube has a longitudinal axis inclined with respect to the longitudinal axis of the burner throat, said second guide tube extending through the plate member and being weldably connected thereto. 